Polyol-Assisted Synthesis of Copper Particles

Copper colloids typically demonstrate excellent catalytic and electric properties, but their synthetic approaches lag behind their more expensive cousins. In this manuscript we investigate the synthesis of Cu colloids using a polyol-based method. We employ phthalonitrile as an additive, leading to competing reactions during the nucleation step and finally resulting in distinct sizes and properties of the copper particles. Even though during the polyol synthesis, the copper particles are partially protected from the high tendency of copper to oxidize, further treatment leads to the formation of a thin passivating and semiconducting Cu_xO layer. Cu_xO is known to be a visible light photocatalyst. We therefore investigate the size-dependent (photo)­catalytic activity of these colloids using rhodamine B (RhB) as a model organic pollutant. Following asymmetrization via deposition of a thin Au layer on one hemisphere, we also demonstrate the applicability as a photocatalytic micromotor.